Single sensor misfire detection apparatus and method for an internal combustion engine

• US 5,361,629 A
• Filed: 08/21/1992
• Issued: 11/08/1994
• Est. Priority Date: 08/21/1992
• Status: Expired due to Term

• Current Assignee: Chrysler Group LLC (Stellantis NV)
• Original Assignee: Chrysler Corporation (Stellantis NV)
• Inventors: McCombie, Jay C.
• Primary Examiner(s): Noland, Tom
• Assistant Examiner(s): Dombroske, George M.
• Application Number:
  US07/934,057
• Time in Patent Office: 809 Days
• Field of Search: 73/116, 73/117.3, 123/419, 364/431.07
• US Class Current: 73/114.04
• CPC Class Codes: G01M 15/11 by detecting misfire

Abstract

A misfire detection apparatus and method is provided for detecting misfire in cylinders of an internal combustion engine in a motor vehicle. The method includes sensing rotation of a crankshaft and calculating a crankshaft velocity based on the sensed rotation of the crankshaft. The method also includes compensating the calculated crankshaft velocity based on a predetermined cylinder. The method further includes comparing either the calculated or compensated crankshaft velocity to a predetermined crankshaft velocity range to determine if therein, and counting a misfire if either the calculated or compensated crankshaft velocity is within the predetermined crankshaft range.

Claims

1. An apparatus to detect misfire in individual cylinders of an internal combustion engine in a motor vehicle, comprising:

means for sensing rotation of a crankshaft;

means connected to said sensing means for calculating a crankshaft velocity based on the sensed rotation of the crankshaft;

means for adaptively compensating the calculated crankshaft velocity based on a predetermined cylinder by subtracting the calculated crankshaft velocity from a previous calculated crankshaft velocity and determining whether the compensated crankshaft velocity is within a predetermined crankshaft velocity range having an upper limit and a lower limit and counting a misfire if the compensated crankshaft velocity is within the upper limit and lower limit of the predetermined crankshaft velocity range.

2. An apparatus to detect misfire in individual cylinders of an internal combustion engine in a motor vehicle, comprising:

means for sensing rotation of a crankshaft;

means connected to said sensing means for calculating a crankshaft velocity based on the sensed rotation of the crankshaft;

means for adaptively compensating the calculated crankshaft velocity based on a predetermined cylinder by subtracting the calculated crankshaft velocity from a previous calculated crankshaft velocity and determining whether the compensated crankshaft velocity is within a predetermined crankshaft velocity range having an upper limit and a lower limit and counting a misfire if the compensated crankshaft velocity is within the upper limit and lower limit of the predetermined crankshaft velocity range; and

target means forming a plurality of trip points on the crankshaft for a predetermined interval of an expansion stroke.

3. An apparatus as set forth in claim 2 wherein said target means comprises a target connected to the crankshaft and having a plurality of teeth formed by slots as said trip points.

4. An apparatus to detect misfire in individual cylinders of an internal combustion engine in a motor vehicle, comprising:

means for sensing rotation of a crankshaft;

means connected to said sensing means for calculating a crankshaft velocity based on the sensed rotation of the crankshaft;

means for adaptively compensating the calculated crankshaft velocity based on a predetermined cylinder by subtracting the calculated crankshaft velocity from a previous calculated crankshaft velocity and determining whether the compensated crankshaft velocity is within a predetermined crankshaft velocity range having an upper limit and lower limit and counting a misfire if the compensated crankshaft velocity is within the upper limit and lower limit of the predetermined range;

a target connected to the crankshaft and having a plurality of teeth formed by slots as trip points on the crankshaft for a predetermined interval of an expansion stroke; and

wherein said sensing means comprises a crankshaft sensor mounted at a fixed point in proximity with said target for sensing edges of said teeth.

5. An apparatus as set forth in claim 4 wherein said sensor is located at a top dead center position relative to a centerline of the crankshaft.

6. An apparatus as set forth in claim 5 wherein said means comprises an electronic control unit.

7. An apparatus to detect misfire in individual cylinders of an internal combustion engine in a motor vehicle, comprising:

a single target connected to a crankshaft and having a plurality of teeth formed by slots to act as trip points;

a single crankshaft sensor mounted at a fixed point in proximity with said single target for sensing edges of said teeth and rotation of the crankshaft;

means connected to said single crankshaft sensor for calculating a crankshaft velocity based on the sensed rotation of the crankshaft and subtracting the calculated crankshaft velocity from a previous calculated crankshaft velocity and determining whether the difference between the calculated crankshaft velocities is within a predetermined crankshaft velocity range having an upper limit and lower limit and counting a misfire if the difference between the calculated crankshaft velocities is within the upper limit and lower limit of the predetermined crankshaft velocity range.

8. An apparatus to detect misfire in individual cylinders of an internal combustion engine in a motor vehicle, comprising:

a target connected to a crankshaft and having a plurality of teeth formed by slots to act as trip points;

a crankshaft sensor mounted at a fixed point in proximity with said target for sensing edges of said teeth and rotation of the crankshaft;

means connected to said sensor for calculating a crankshaft velocity based on the sensed rotation of the crankshaft and determining whether the calculated crankshaft velocity is within a predetermined velocity range and counting a misfire if the calculated crankshaft velocity is within the predetermined velocity range; and

wherein said target is generally circular and said teeth are spaced circumferentially at a nine degree and sixty-nine degree interval for an expansion stroke.

9. An apparatus as set forth in claim 8 wherein said crankshaft sensor is mounted at top dead center relative to the crankshaft.

10. An apparatus to detect misfire in individual cylinders of an internal combustion engine in a motor vehicle, comprising;

a single target connected to the crankshaft and having a plurality of teeth formed by slots to act as trip points;

a single crankshaft sensor mounted at a fixed point in proximity with said single target for sensing edges of said teeth and rotation of the crankshaft, said single crankshaft sensor being mounted at top dead center relative to the crankshaft;

means connected to said single crankshaft sensor for calculating a crankshaft velocity based on the sensed rotation of the crankshaft and subtracting the calculated crankshaft velocity from a previous calculated crankshaft velocity and determining whether the difference between the calculated crankshaft velocities is within a predetermined crankshaft velocity range having an upper limit and lower limit and counting a misfire if the difference between the calculated crankshaft velocities is within the upper limit and lower limit of the predetermined crankshaft velocity range.

11. A method of detecting misfire in individual cylinders of an internal combustion engine in a motor vehicle, said method comprising the steps of:

sensing rotation of a crankshaft;

calculating a crankshaft velocity based on the sensed rotation of the crankshaft;

adaptively compensating the calculated crankshaft velocity based on a predetermined cylinder by subtracting the calculated crankshaft velocity from a previous calculated crankshaft velocity;

comparing the compensated crankshaft velocity to a predetermined crankshaft velocity range having an upper limit and lower limit to determine if therein; and

counting a misfire if the compensated crankshaft velocity is within the upper limit and lower limit of the predetermined crankshaft velocity range.

12. A method as set forth in claim 11 wherein said step of sensing comprises starting a timer when a crankshaft sensor detects a beginning of a predetermined interval of an expansion stroke and stopping the timer when the crankshaft sensor detects an end of the predetermined interval.

13. A method as set forth in claim 11 including the step of locating the crankshaft sensor at a top dead center position relative to the crankshaft.

14. A method as set forth in claim 11 including the step of forming a target on the crankshaft with teeth spaced circumferentially to form the predetermined interval.

15. A method of detecting misfire in individual cylinders of an internal combustion engine in a motor vehicle, said method comprising the steps of:

forming a target on a crankshaft with teeth spaced circumferentially to form a predetermined interval;

sensing rotation of the crankshaft;

starting a timer when the crankshaft sensor detects a sixty-nine degree edge of a tooth on the target;

stopping the timer when the crankshaft sensor detects a nine degree edge of a tooth on the target;

calculating a crankshaft velocity based on the sensed rotation of the crankshaft and the time elapsed on the timer;

compensating the calculated crankshaft velocity based on a predetermined cylinder by subtracting the calculated crankshaft velocity from a previous calculated crankshaft velocity;

comparing the compensated crankshaft velocity to a predetermined crankshaft velocity range having an upper limit and a lower limit to determine if therein; and

counting a misfire if the compensated crankshaft velocity is within the upper limit and lower limit of the predetermined crankshaft velocity range.

16. A method of detecting misfire in individual cylinders of an internal combustion engine in a motor vehicle, said method comprising the steps of:

forming a target on a crankshaft with teeth spaced circumferentially to form a predetermined interval;

sensing rotation of the crankshaft;

starting a timer when a crankshaft sensor detects a sixty-nine degree edge of a tooth on the target;

stopping the timer when the crankshaft sensor detects a nine degree edge of a tooth on the target;

calculating a crankshaft velocity based on the sixty degree difference between edges of the teeth and the time elapsed on the timer;

compensating the calculated crankshaft velocity based on a predetermined cylinder by subtracting the calculated crankshaft velocity from a previous calculated crankshaft velocity;

comparing the compensated. crankshaft velocity to a predetermined crankshaft velocity range having an upper limit and a lower limit to determine if therein; and

counting a misfire if the compensated crankshaft velocity is within the upper limit and lower limit of the predetermined crankshaft velocity range.

17. A method of detecting misfire in individual cylinders of an internal combustion engine in a motor vehicle, said method comprising the steps of:

forming a target on a crankshaft with teeth spaced circumferentially about every sixty degrees;

locating a crankshaft sensor at a top dead center position relative to the crankshaft;

sensing rotation of a crankshaft by starting a timer when the crankshaft sensor detects an edge of a tooth and stopping the timer when the crankshaft sensor detects an edge of another tooth for the sixty degree interval;

calculating a crankshaft velocity based on the sixty degree difference between the edges of the teeth and the time elapsed on the timer;

compensating the calculated crankshaft velocity by subtracting the calculated crankshaft velocity from a previous calculated crankshaft velocity;

comparing the compensated crankshaft velocity to a predetermined crankshaft velocity range having an upper limit and a lower limit to determine if therein and

counting a misfire if the compensated crankshaft velocity is within the upper limit and lower limit of the predetermined crankshaft velocity range.